Long PR & Short QT on Digoxin Therapy

Report:

Sinus rhythm 75/min

Second degree AV block, Möbitz 1 (Wenckebach)

Short QT interval 0.29”

QTc 0.32”

Diffuse nonspecific ST/T changes

Consistent with digoxin effect and toxicity

Comment:

Hospital may be a dangerous place but I would not send a 61 year old home from Casualty with the diagnosis of recurrent vaso-vagal syncope. Not is she had EF of 10% and 2o AV block on her ECG.

The line between digoxin toxicity and “effect” can be drawn in many places – ventricular bigeminy, bradycardias, blocks, etc. It is rarely completely clear if the drug is still therapeutic or by now harmful or dangerous. Even marked 1o AV block can do a lot of damage in the right setting27.

A propos, 1o AV block is not routinely reported if 2o one is present as well.

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